"""Unittest for UndoDelegator in idlelib.undo.py.

Coverage about 80% (retest).
"""
from test.support import requires
requires('gui')

import unittest
from unittest.mock import Mock
from tkinter import Text, Tk
from idlelib.undo import UndoDelegator
from idlelib.percolator import Percolator


class UndoDelegatorTest(unittest.TestCase):

    @classmethod
    def setUpClass(cls):
        cls.root = Tk()
        cls.text = Text(cls.root)
        cls.percolator = Percolator(cls.text)

    @classmethod
    def tearDownClass(cls):
        cls.percolator.redir.close()
        del cls.percolator, cls.text
        cls.root.destroy()
        del cls.root

    def setUp(self):
        self.delegator = UndoDelegator()
        self.delegator.bell = Mock()
        self.percolator.insertfilter(self.delegator)

    def tearDown(self):
        self.percolator.removefilter(self.delegator)
        self.text.delete('1.0', 'end')
        self.delegator.resetcache()

    def test_undo_event(self):
        text = self.text

        text.insert('insert', 'foobar')
        text.insert('insert', 'h')
        text.event_generate('<<undo>>')
        self.assertEqual(text.get('1.0', 'end'), '\n')

        text.insert('insert', 'foo')
        text.insert('insert', 'bar')
        text.delete('1.2', '1.4')
        text.insert('insert', 'hello')
        text.event_generate('<<undo>>')
        self.assertEqual(text.get('1.0', '1.4'), 'foar')
        text.event_generate('<<undo>>')
        self.assertEqual(text.get('1.0', '1.6'), 'foobar')
        text.event_generate('<<undo>>')
        self.assertEqual(text.get('1.0', '1.3'), 'foo')
        text.event_generate('<<undo>>')
        self.delegator.undo_event('event')
        self.assertTrue(self.delegator.bell.called)

    def test_redo_event(self):
        text = self.text

        text.insert('insert', 'foo')
        text.insert('insert', 'bar')
        text.delete('1.0', '1.3')
        text.event_generate('<<undo>>')
        text.event_generate('<<redo>>')
        self.assertEqual(text.get('1.0', '1.3'), 'bar')
        text.event_generate('<<redo>>')
        self.assertTrue(self.delegator.bell.called)

    def test_dump_event(self):
        """
        Dump_event cannot be tested directly without changing
        environment variables. So, test statements in dump_event
        indirectly
        """
        text = self.text
        d = self.delegator

        text.insert('insert', 'foo')
        text.insert('insert', 'bar')
        text.delete('1.2', '1.4')
        self.assertTupleEqual((d.pointer, d.can_merge), (3, True))
        text.event_generate('<<undo>>')
        self.assertTupleEqual((d.pointer, d.can_merge), (2, False))

    def test_get_set_saved(self):
        # test the getter method get_saved
        # test the setter method set_saved
        # indirectly test check_saved
        d = self.delegator

        self.assertTrue(d.get_saved())
        self.text.insert('insert', 'a')
        self.assertFalse(d.get_saved())
        d.saved_change_hook = Mock()

        d.set_saved(True)
        self.assertEqual(d.pointer, d.saved)
        self.assertTrue(d.saved_change_hook.called)

        d.set_saved(False)
        self.assertEqual(d.saved, -1)
        self.assertTrue(d.saved_change_hook.called)

    def test_undo_start_stop(self):
        # test the undo_block_start and undo_block_stop methods
        text = self.text

        text.insert('insert', 'foo')
        self.delegator.undo_block_start()
        text.insert('insert', 'bar')
        text.insert('insert', 'bar')
        self.delegator.undo_block_stop()
        self.assertEqual(text.get('1.0', '1.3'), 'foo')

        # test another code path
        self.delegator.undo_block_start()
        text.insert('insert', 'bar')
        self.delegator.undo_block_stop()
        self.assertEqual(text.get('1.0', '1.3'), 'foo')

    def test_addcmd(self):
        text = self.text
        # when number of undo operations exceeds max_undo
        self.delegator.max_undo = max_undo = 10
        for i in range(max_undo + 10):
            text.insert('insert', 'foo')
            self.assertLessEqual(len(self.delegator.undolist), max_undo)

if __name__ == '__main__':
    unittest.main(verbosity=2, exit=False)
